The present invention relates to a method and apparatus for preparing varying degrees of gloss on printed matter in printing machines, which produces printed images on printed matter by application of an ink layer.
Varying degrees of gloss on a surface of printed matter is usually produced by printing plates used as coating plates, which are especially made for this purpose. These printing plates have partial recesses. The process is described in the 9th edition of the book xe2x80x9cOffsetdrucktechnikxe2x80x9d (Offset printing) by Helmut Teschner on pages 11 to 43. The book also describes the limitation of this technique that fractional heavy overprinting is required for particular protruding gloss effects.
The costly manufacturing of the coating plates is also disadvantageous. Multi-stepped gloss effects on a printed image require a lot of efforts by using multiple coating plates in multiple coating units.
An object of the present invention is to establish a method for producing varying degrees of gloss on printed matter with only one coating tower comprising only one coating unit and no especially manufactured coating plate.
The present invention accomplishes this by producing a method comprising applying an ink layer from at least two different ink systems on a substrate to be printed to produce a printing image. The printed image is subsequently coated with a coating, whereby each ink system changes degree of gloss in reaction with the coating layer.
The present invention has an advantage that varying degrees of gloss can be produced with only one coating plate without partial recesses. The manufacturing costs for the coating plate is decreased. The coating plate can be used for several printing jobs so that the make ready time is reduced. Furthermore, only one coating unit or coating tower is required.